Nazca Lines Theories & Aliens?

I've read all the Nazca Lines theories that claim the mysterious lines are based on an advanced early civilization that history never recorded. I wonder if it's possible to think of early men having contact with aliens and the possibility that UFOs once land in a remote corner of South America. What do you people think?
Are all the Nazca lines theories explained by the existence of aliens?

There are certainly people who say that all the Nazca lines were made by aliens. If so, whoever used them must have been able erase all evidence of their existence and activities, including evidence of actual take-offs and landings that aliens left behind. The Nazca lines are truly mysterious. We could see in an experiment that a man was able to recreate them using only the technological knowledge and means known by that time. So, we could assume that this could be just messages to their gods and nothing further; the doubt is clinging, though. I think aliens had something to do with the Nazca lines.